Wednesday, October 27, 2004

Monkey "Closed Loop" Manipulation

If a monkey is hungry but has his arms pinned, there's not much he can do about it. Unless that monkey can control a nearby robotic arm with his brain.

And that's exactly what the monkey in Andrew Schwartz 's neurobiology lab at the University of Pittsburgh can do, feeding himself using a prosthetic arm controlled solely by his thoughts.

If mastered, the technology could be used to help spinal cord injuries, amputees or stroke victims. "I still think prosthetics is at an early stage ... but this is a big step in the right direction," said Chance Spalding, a bioengineering graduate student who worked on the project.

[snip]

The unique aspect of Schwartz's research is that he conducted what is known as "closed loop" brain experiments. In a "closed loop" experiment, the monkey is conscious of the robotic arm and is making an effort to control it. Monkeys in previous experiments did not understand that they were having an effect on the world at all. Duke University performed such prosthetic arm experiments as far back as 2000. In one case they even sent the electrode signals over the internet , allowing the monkey to move an arm 600 miles away at MIT.

"The open loop experiment was really very crude," said Schwartz. "The closed loop introduces us into a whole new field because the animal actually sees the arm and the consequence of what it is doing." For Schwartz's monkey the robotic arm is incorporated into its mental body representation, making it an extra limb.